determined it is in our vital national interest to send an additional 30,000 troops to afghanistan. >> reporter: at that time, he set a schedule for their withdrawal, a goal that has been met. 33,000 u.s. troops took part in the surge. 10,000 of them were out by july of last year. and the remaining 23,000 are now gone. in his statement, the defense secretary had a sobering reminder. saying, it is important to underscore that even as our surge troops return home, there's roughly 68,000 americans who remain in a tough fight in afghanistan, alongside their nato and afghan partners. we are a nation at war. the human toll of the surge was tremendous. after the almost 200 u.s. casualties in afghanistan, 57% happened during the surge. now, those who remain face the die-hard insurgents and the growing threat of insider attacks. the deadlines to bring the final american troops home is still 2014. muhammad lila, abc news, kabul.